diff --git a/Doc/library/urllib.error.rst b/Doc/library/urllib.error.rst
--- a/Doc/library/urllib.error.rst
+++ b/Doc/library/urllib.error.rst
@@ -29,16 +29,21 @@ The following exceptions are raised by :
 
 .. exception:: HTTPError
 
    Though being an exception (a subclass of :exc:`URLError`), an
    :exc:`HTTPError` can also function as a non-exceptional file-like return
    value (the same thing that :func:`urlopen` returns).  This is useful when
    handling exotic HTTP errors, such as requests for authentication.
 
+   .. attribute:: reason
+
+      The reason for this error. It can be a message string or another
+      exception instance.
+
    .. attribute:: code
 
       An HTTP status code as defined in `RFC 2616
       <http://www.faqs.org/rfcs/rfc2616.html>`_.  This numeric value corresponds
       to a value found in the dictionary of codes as found in
       :attr:`http.server.BaseHTTPRequestHandler.responses`.
 
 .. exception:: ContentTooShortError(msg, content)